[FEAT/BE] fixing remaining stock check closing response

internal/modules/closings/dto/closingSapronak.dto.go

@@ -65,7 +65,7 @@ type SapronakCategoryRowDTO struct {
 	QtyOut          float64 `json:"qty_out"`
 	QtyUsed         float64 `json:"qty_used"`
 	Description     string  `json:"description"`
-	ProductCategory []string `json:"product_category"`
+	ProductCategory string  `json:"product_category"`
 	UnitPrice       float64 `json:"unit_price"`
 	TotalAmount     float64 `json:"total_amount"`
 	Notes           string  `json:"notes"`
@@ -183,13 +183,13 @@ func ToSapronakProjectAggregatedFromReport(report *SapronakReportDTO, flag strin
 		"PULLET": 0,
 	}
 
-	buildFlagList := func(productID uint, fallback string) []string {
+	buildFlagList := func(productID uint, fallback string) string {
 		rawFlags := productFlags[productID]
 		if len(rawFlags) == 0 {
 			if fallback == "" {
-				return []string{}
+				return ""
 			}
-			return []string{fallback}
+			return fallback
 		}
 		seen := make(map[string]struct{}, len(rawFlags))
 		ordered := make([]string, 0, len(rawFlags))
@@ -220,7 +220,7 @@ func ToSapronakProjectAggregatedFromReport(report *SapronakReportDTO, flag strin
 			}
 			return li < lj
 		})
-		return ordered
+		return strings.Join(ordered, " ")
 	}
 
 	for _, group := range report.Groups {